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  1. Removal of caffeine from aqueous solution by indirect electrochemical oxidation using a graphite-PVC composite electrode: A role of hypochlorite ion as an oxidising agent
    Al-Qaim FF, Mussa ZH, Othman MR, Abdullah MP
    J Hazard Mater, 2015 Dec 30;300:387-397.
    PMID: 26218306 DOI: 10.1016/j.jhazmat.2015.07.007
    The electrochemical oxidation of caffeine, a widely over-the-counter stimulant drug, has been investigated in effluent wastewater and deionized water (DIW) using graphite-poly vinyl chloride (PVC) composite electrode as anode. Effects of initial concentration of caffeine, chloride ion (Cl(-)) loading, presence of hydrogen peroxide (H2O2), sample volume, type of sample and applied voltage were determined to test and to validate a kinetic model for the oxidation of caffeine by the electrochemical oxidation process. The results revealed that the electrochemical oxidation rates of caffeine followed pseudo first-order kinetics, with rate constant values ranged from 0.006 to 0.23 min(-1) depending on the operating parameters. The removal efficiency of caffeine increases with applied voltage very significantly, suggesting a very important role of mediated oxidation process. However, the consumption energy was considered during electrochemical oxidation process. In chloride media, removal of caffeine is faster and more efficiently, although occurrence of more intermediates takes place. The study found that the adding H2O2 to the NaCl solution will inhibit slightly the electrochemical oxidation rate in comparison with only NaCl in solution. Liquid chromatography-time of flight-mass spectrometry (LC-TOF-MS) technique was applied to the identification of the by-products generated during electrochemical oxidation, which allowed to construct the proposed structure of by-products.
    Matched MeSH terms: Central Nervous System Stimulants/isolation & purification*; Central Nervous System Stimulants/toxicity
  2. Fulltext Amphetamine type stimulant (ATS) induced psychosis: A rising problems in Malaysia
    Ahmad, H.S.
    Malaysian Journal of Psychiatry, 2008;17(2):1-4.
    MyJurnal
    The past decade has seen a marked increase in the popularity of ATS use, particularly methamphetamine, within East Asia,and the Pacific region. In Malaysia, the National Anti Drug Agency has identified 8,870 addicts (from January till August 2008) out of which 1,126 was ATS dependence. During the same period, the police have arrested 46,388 people under the Dangerous Drug Act 1952. They also has seize 283kg of syabu, 545kg of ecstacy powder, 66194 tablets of esctacy pills and 222,376 tablets of yaba pills from Jan till August this year. The occurrence of psychosis arising from the use of ATS was first reported in the late 1930's. With growing ATS use, particularly methamphetamine, ATS-induced psychosis has become a major impact on public health.Symptoms of ATS-induced psychosis: Methamphetamine use produces a variety of effects, ranging from irritability, to physical aggression, hyperawareness, hypervigilance, and psychomotor agitation. Repeated or high-dose use of the stimulant can cause drug-induced psychosis resembling paranoid schizophrenia, characterized by hallucinations, delusions and thought disorders. When used in long term, methamphetamine may lead to development of psychiatric symptoms due to dopamine depletion in the striatum. The most common lifetime psychotic symptoms among methamphetamine psychotic patients - as reported in a cross-country study involving Australia, Japan, the Philippines and Thailand - are persecutory delusion, auditory hallucinations, strange or unusual beliefs and thought reading. Those patients were also reported to suffer from impaired speech, psychomotor retardation, depression and anxiety. An ATS psychosis can be distinguished from primary psychotic disorders by time. In ATS-induced psychosis symptoms usually resolve after the drug is discontinued. If symptoms do not resolve within 2 weeks after cessation of stimulant use, a primary psychiatric disorder should be suspected. When compared with other stimulants, such as cocaine, psychosis is induced more commonly by ATS, possibly due to the longer duration of action produced by amphetamines.For example, while smoking cocaine produces a high that lasts for 20-30 minutes, smoking methamphetamine produces a high that lasts 8-24 hours. Other symptoms of ATS-induced psychosis reported include affective blunting,(6) violent behavior, and self-mutilation and self-injurious behavior.
    Matched MeSH terms: Central Nervous System Stimulants
  3. Effects of aqueous extract of Prismatomeris glabra root on non-spatial memory in rats using object discrimination test
    Norazrina Azmi, Loh WT, Siti Suriani Omar, Juriyati Jalil, Aishah Adam
    Sains Malaysiana, 2011;40:1097-1103.
    The aqueous extract of Prismatomeris glabra root has been used traditionally in Malaysia by the aborigines and certain rural Malays for its ergogenic effects, to maintain wellness and to enhance physical stamina. It has also been used as an aphrodisiac for generations in the east coast of Peninsular Malaysia. Previous studies have shown that plants with ergogenic effects may also act as a stimulant and impair cognitive function. Therefore, we seek to investigate the effects of P. glabra on non-spatial memory in male Sprague Dawley rats using object recognition test. Trial rats were injected intraperitoneally with an aqueous extract of P. glabra roots at doses of 50 and 100 mg/kg for the acute (30 min) and subacute (7 days) studies. Scopolamine (0.3 mg/kg) was used as a positive control only in the acute study meanwhile control rats were injected with saline. The locomotor activity of rats was also determined in the same test. We demonstrated that groups treated with 50 and 100 mg/kg of the extract lost their ability to discriminate the novel from familiar object in choice phase and did not alter the locomotor activity in both studies. Our results also indicated that the deficits in non-spatial working memory occured at these doses were not due to impaired locomotor activity.
    Matched MeSH terms: Central Nervous System Stimulants
  4. Immunomodulatory effects of Potentilla indica and Dendrophthoe pentandra on mice splenocytes and thymocytes
    Ang HY, Subramani T, Yeap SK, Omar AR, Ho WY, Abdullah MP, et al.
    Exp Ther Med, 2014 Jun;7(6):1733-1737.
    PMID: 24926376
    Immunomodulators are agents that are able to stimulate or inhibit the immune response. The leaf extracts from Potentilla indica and Dendrophthoe pentandra were analyzed in vitro for immunomodulatory activity and an MTT colorimetric assay was conducted to determine the proliferation of mice splenocytes and thymocytes. A bromodeoxyuridine assay was performed to analyze DNA synthesis and the Trypan blue exclusion method was conducted to evaluate the changes in total cell population. The results indicated that treatment with P. indica and D. pentandra produced a time- and dose-dependent increase in cell viability and proliferation. Following 72 h of treatment with P. indica and D. pentandra, thymocyte proliferation was augmented by 18 and 41%, respectively and splenocyte proliferation increased by 35 and 42%, respectively, when compared with untreated cells. The present study demonstrated that these extracts may act as potential immunostimulants and, thus, represent an alternative source of immunomodulatory compounds for the treatment of human immune-mediated diseases.
    Matched MeSH terms: Central Nervous System Stimulants
  5. Latent class analysis of substance use among men who have sex with men in Malaysia: Findings from the Asian Internet MSM Sex Survey
    Lim SH, Cheung DH, Guadamuz TE, Wei C, Koe S, Altice FL
    Drug Alcohol Depend, 2015 Jun 1;151:31-7.
    PMID: 25865907 DOI: 10.1016/j.drugalcdep.2015.02.040
    BACKGROUND: High prevalence of substance use among men who have sex with men (MSM) may drive the HIV epidemic in Malaysia but patterns of substance use among Malaysian MSM have not been examined. Our study investigated specific Malaysian MSM risk groups to determine the association between their substance use and sexual risk behaviors.
    METHODS: Data from Malaysian respondents (n=1235) in a large, multinational online survey of Asian MSM in 2010 were used to identify latent classes of substance use. Subsequent covariates were included in a joint model to predict class membership.
    RESULTS: The 3-class model was identified as the best fitting model, which included: (1) 'negligible substance use' for those reporting none or using any substance sparingly; (2) 'soft substance use' for those using poppers, ecstasy and drinking before sex; and (3) 'amphetamine-type stimulant (ATS) use' for those using stimulants (methamphetamine, ecstasy), erectile dysfunction drugs and recreational drug use before sex. Men in the 'ATS use' category were significantly less likely to not know their HIV status (AOR: 0.30, 95%CI: 0.14,0.66), more likely to have had more than 6 male sex partners (AOR: 4.83, 95% CI: 1.92-12.2), to have group sex (AOR:4.07, 95% CI: 2.31-7.15), to report inconsistent condom use (AOR:2.01, 95% CI: 1.12-3.60), to be HIV-infected (AOR:3.92, 95% CI: 1.63-8.42) and to have had any sexually transmitted infections (AOR:3.92, 95% CI:1.70, 9.08), compared to men in the 'negligible substance use' category.
    CONCLUSIONS: Our study identified subgroups of Malaysian MSM with distinct substance use patterns and HIV-related risk profiles, which provides implication for targeting HIV prevention in this subpopulation.
    Matched MeSH terms: Central Nervous System Stimulants
  6. Fulltext Early Initiation of Amphetamine-Type Stimulants (ATS) Use Associated with Lowered Cognitive Performance among Individuals with Co-Occurring Opioid and ATS Use Disorders in Malaysia
    Chooi WT, Mohd Zaharim N, Desrosiers A, Ahmad I, Yasin MAM, Syed Jaapar SZ, et al.
    J Psychoactive Drugs, 2017 06 29;49(4):326-332.
    PMID: 28661714 DOI: 10.1080/02791072.2017.1342152
    Amphetamine-type stimulants (ATS) use is increasingly prevalent in Malaysia, including among individuals who also use opioids. We evaluated cognitive functioning profiles among individuals with co-occurring opioid and ATS dependence and their lifetime patterns of drug use. Participants (N = 50) enrolling in a clinical trial of buprenorphine/naloxone treatment with or without atomoxetine completed the Raven's Standard Progressive Matrices, Rey-Osterrieth Complex Figure Test, Digit Span, Trail Making and Symbol Digit Substitution tasks. Multidimensional scaling and a K-means cluster analyses were conducted to classify participants into lower versus higher cognitive performance groups. Subsequently, analyses of variance procedures were conducted to evaluate between group differences on drug use history and demographics. Two clusters of individuals with distinct profiles of cognitive performance were identified. The age of ATS use initiation, controlling for the overall duration of drug use, was significantly earlier in the lower than in the higher cognitive performance cluster: 20.9 (95% CI: 18.0-23.8) versus 25.2 (95% CI: 22.4-28.0, p = 0.038). While adverse effects of ATS use on cognitive functioning can be particularly pronounced with younger age, potentially related to greater vulnerability of the developing brain to stimulant and/or neurotoxic effects of these drugs, the current study findings cannot preclude lowered cognitive performance before initiation of ATS use.
    Matched MeSH terms: Central Nervous System Stimulants/adverse effects*
  7. A Novel Liquid Chromatography Tandem Mass Spectrometry Technique using Multi-Period-Multi-Experiment of MRM-EPI-MRM3 with Library Matching for Simultaneous Determination of Amphetamine Type Stimulants Related Drugs in Whole Blood, Urine and Dried Blood Stain (DBS)-Application to Forensic Toxicology Cases in Malaysia
    Zubaidi FA, Choo YM, Tan GH, Hamid HA, Choy YK
    J Anal Toxicol, 2019 Aug 23;43(7):528-535.
    PMID: 31141150 DOI: 10.1093/jat/bkz017
    A novel mass spectrometry detection technique based on a multi-period and multi- experiment (MRM-EPI-MRM3) with library matching in a single run for fast and rapid screening and identification of amphetamine type stimulants (ATS) related drugs in whole blood, urine and dried blood stain was developed and validated. The ATS-related drugs analyzed in this study include ephedrine, pseudoephedrine, amphetamine, methamphetamine, MDMA (3,4-Methylenedioxymethamphetamine), MDA (3,4-Methylenedioxyamphetamine), MDEA (3,4-Methylenedioxy-N-ethylamphetamine) and phentermine. The relative standard deviation for inter and intraday was less than 15% while recoveries ranged from 80% to 120% for all three matrices, i.e., whole blood, urine and dried blood stain. All compounds gave library matching percentage of more than 85% based on the purity. This method was proven to be simple and robust, and provide high confident results complemented with library matching confirmation.
    Matched MeSH terms: Central Nervous System Stimulants
  8. Fulltext Following "the Roots" of Kratom (Mitragyna speciosa): The Evolution of an Enhancer from a Traditional Use to Increase Work and Productivity in Southeast Asia to a Recreational Psychoactive Drug in Western Countries
    Cinosi E, Martinotti G, Simonato P, Singh D, Demetrovics Z, Roman-Urrestarazu A, et al.
    Biomed Res Int, 2015;2015:968786.
    PMID: 26640804 DOI: 10.1155/2015/968786
    The use of substances to enhance human abilities is a constant and cross-cultural feature in the evolution of humanity. Although much has changed over time, the availability on the Internet, often supported by misleading marketing strategies, has made their use even more likely and risky. This paper will explore the case of Mitragyna speciosa Korth. (kratom), a tropical tree used traditionally to combat fatigue and improve work productivity among farm populations in Southeast Asia, which has recently become popular as novel psychoactive substance in Western countries. Specifically, it (i) reviews the state of the art on kratom pharmacology and identification; (ii) provides a comprehensive overview of kratom use cross-culturally; (iii) explores the subjective experiences of users; (iv) identifies potential risks and side-effects related to its consumption. Finally, it concludes that the use of kratom is not negligible, especially for self-medication, and more clinical, pharmacological, and socioanthropological studies as well as a better international collaboration are needed to tackle this marginally explored phenomenon.
    Matched MeSH terms: Central Nervous System Stimulants
  9. The risk and associated factors of methamphetamine psychosis in methamphetamine-dependent patients in Malaysia
    Sulaiman AH, Said MA, Habil MH, Rashid R, Siddiq A, Guan NC, et al.
    Compr Psychiatry, 2014 Jan;55 Suppl 1:S89-94.
    PMID: 23433219 DOI: 10.1016/j.comppsych.2013.01.003
    The objective of this study was to determine the risk of lifetime and current methamphetamine-induced psychosis in patients with methamphetamine dependence. The association between psychiatric co-morbidity and methamphetamine-induced psychosis was also studied.
    Matched MeSH terms: Central Nervous System Stimulants/adverse effects*
  10. Combination of transcranial direct current stimulation and methylphenidate in subacute stroke
    Wang QM, Cui H, Han SJ, Black-Schaffer R, Volz MS, Lee YT, et al.
    Neurosci Lett, 2014 May 21;569:6-11.
    PMID: 24631567 DOI: 10.1016/j.neulet.2014.03.011
    Noninvasive transcranial direct current stimulation (tDCS) and methylphenidate (MP) are associated with motor recovery after stroke. Based on the potentially complementary mechanisms of these interventions, we examined whether there is an interactive effect between MP and tDCS. In this preliminary study, we randomized subacute stroke subjects to receive tDCS alone, MP alone or combination of tDCS and MP. A blinded rater measured safety, hand function, and cortical excitability before and after treatment. None of the treatments caused any major or severe adverse effects or induced significant differences in cortical excitability. Analysis of variance of gain score, as measured by Purdue pegboard test, showed a significant between-group difference (F(2,6)=12.167, p=0.008). Post hoc analysis showed that the combination treatment effected greater Purdue pegboard gain scores than tDCS alone (p=0.017) or MP alone (p=0.01). Our preliminary data with nine subjects shows an interesting dissociation between motor function improvement and lack of motor corticospinal plasticity changes as indexed by transcranial magnetic stimulation in subacute stroke subjects.
    Matched MeSH terms: Central Nervous System Stimulants/therapeutic use*
  11. Fulltext Pharmacotherapy for comorbid adult attention-deficit hyperactivity disorder and stimulant dependence: a systematic review
    Woon, L.S., Hazli Z., Gan, L.L.Y.
    International Medical Journal Malaysia, 2018;17(2):149-161.
    MyJurnal
    Comorbid adult attention-deficit hyperactivity disorder (ADHD) and stimulant dependence is widely recognized, but efficacy of pharmacotherapy in this patient population is not well established. We aimed to review whether pharmacotherapy is efficacious in reducing ADHD symptoms and stimulant use in comorbid adult ADHD and stimulant use disorder. English articles until June 2017 were systematically searched in electronic databases (MEDLINE and PsycINFO), an online clinical trials register (ClinicalTrial.gov), and through hand-search of article references. Randomized, double-blind, placebo-controlled trials that studied efficacy of pharmacotherapy in adults with comorbid ADHD and stimulant dependence were included. Two reviewers assessed studies for inclusion and extracted data; disagreements were resolved by consensus. Study outcomes included were changes in ADHD symptom severity, substance abstinence, treatment retention rates and safety. From the 1394 records identified, five trials (n=358) were included. Four studies involved methylphenidate; in another study extended-release mixed amphetamine were used. The comorbid stimulant was cocaine in three studies, and amphetamines in the rest. All were short-term studies involving predominantly young male adults conducted in outpatient settings. There is early promising but mixed evidence for therapeutic efficacy in improving ADHD symptoms. Stimulant medications did not worsen stimulant dependence or adverse effects of stimulant medications. Side effects were mild and tolerable. High attrition rates and small sample size limited the generalizability of findings. Current limited evidence suggests that stimulant treatment for comorbid adult ADHD and stimulant dependence is feasible. Welldesigned trials with adequate power are needed for more robust evidence on ADHD and stimulant use outcomes.
    Matched MeSH terms: Central Nervous System Stimulants
  12. Histopathological studies of cardiac lesions after long term administration of methamphetamine in high dosage--Part II
    Islam MN, Jesmine K, Kong Sn Molh A, Hasnan J
    Leg Med (Tokyo), 2009 Apr;11 Suppl 1:S147-50.
    PMID: 19345131 DOI: 10.1016/j.legalmed.2009.02.035
    A small amount of Methamphetamine (MA) can produce behavioural changes such as euphoria, increased alertness, paranoia, decreased appetite and increased physical activity. In cardiovascular system, it can produce chest pain and hypertension which can result in cardiovascular collapse. In addition, MA causes accelerated heartbeat, elevated blood pressure. It can also cause irreversible damage to blood vessels in the brain. A number of sympathomimetic amines are capable of causing myocardial damage, but the cardio-toxic action of MA has been of particular interest since standardized dosage consistently produces myocardial lesions. As this drug is a choice of many teenagers and young adults, the damage to their health, as well as their future aspects could be greatly affected, therefore more evidence must be sought to convince them the negative root and show them the optimism of recovery and salvation. To clarify the effect of Methamphetamine (MA) on myocardium, 56 male Wister rats aged four weeks were divided equally into MA, Methamphetamine withdrawal (MW), Placebo (P) and Control (C) group were examined following daily intra-peritoneal administration of MA at a dose of 5 mg/kg body weight for 2, 4, 8 and 12 weeks. Normal saline was similarly injected in P group. Light microscopic changes was seen in the myocardium of MA treated group including eosinophilic degeneration, atrophy, hypertrophy, disarray, edema, cellular infiltration, myolysis, granulation tissue, fibrosis and vacuolization. On the other hand, the withdrawal group showed evidence of gradual recovery of those myocardial changes. Optimism is therefore generated about possibility of returning towards normal by withdrawing of this drug by the addicts.
    Matched MeSH terms: Central Nervous System Stimulants/toxicity*
  13. Differentiation of Commercially Available Kratom by Purported Country of Origin using Inductively Coupled Plasma-Mass Spectrometry
    Braley C, Hondrogiannis EM
    J Forensic Sci, 2020 Mar;65(2):428-437.
    PMID: 31560807 DOI: 10.1111/1556-4029.14201
    Kratom is a plant material exhibiting both analgesic and stimulant effects and is also forensically relevant since it is abused as a "legal high." It is regulated in several countries but not scheduled in the United States at the federal level. This study used inductively coupled plasma-mass spectrometry (ICP-MS) to measure the concentrations of 13 elements in 19 kratom samples obtained from an online distributor selling kratom, from Borneo, Malaysia, Indonesia, Thailand, and Vietnam, for the purpose of using the elements to discriminate among purported country of origin, "suborigin," and strain. Analysis of variance revealed statistical differences in concentrations of elements from each group, while discriminant function analysis (using leave-one-out classification) successfully classified kratom samples by their purported country of origin (100%), "suborigin," (100%), and strain (86%). Our method illustrates the possibility of utilizing ICP-MS for determination of commercially available kratom samples by purported origin, "subororign," or by product line.
    Matched MeSH terms: Central Nervous System Stimulants
  14. Fulltext Triterpene composition and bioactivities of Centella asiatica
    Hashim P, Sidek H, Helan MH, Sabery A, Palanisamy UD, Ilham M
    Molecules, 2011;16(2):1310-22.
    PMID: 21278681 DOI: 10.3390/molecules16021310
    Leaves of Centella asiatica (Centella) were analysed for their triterpene composition and bioactivity such as collagen enhancement, antioxidant, anticellulite and UV protection capacity properties. Triterpenes of Centella were measured using HPLC-PAD on an Excil ODS 5 mm (C18) column for the simultaneous determination of asiatic acid, madecassic acid, asiaticoside and madecassoside. Centella was found to contain significant amounts of madecassoside (3.10 ± 4.58 mg/mL) and asiaticoside (1.97 ± 2.65 mg/mL), but was low in asiatic and madecassic acid. The highest collagen synthesis was found at 50 mg/mL of Centella extracts. The antioxidant activity of Centella (84%) was compared to grape seed extract (83%) and Vitamin C (88%). Its lipolytic activity was observed by the release of glycerol (115.9 µmol/L) at 0.02% concentration. Centella extracts exhibited similar UV protection effect to OMC at 10% concentration. In view of these results, the potential application of Centella in food and pharmaceutical industries is now widely open.
    Matched MeSH terms: Central Nervous System Stimulants/pharmacology
  15. Leave methamphetamine to be alive--Part II
    Islam MN, Khan J, Jaafar H
    Leg Med (Tokyo), 2009 Apr;11 Suppl 1:S143-6.
    PMID: 19345604 DOI: 10.1016/j.legalmed.2009.02.045
    Series of experiments have been completed with Methamphetamine (MA). Some were with the higher, medium or lower duration of MA administration and some were with acute or chronic doses. Whatever may be the dose or duration the ultimate result came out with the further establishment of cardio-toxic effect of this drug. Cardiovascular symptoms related to MA toxicity include chest pain, palpitations, dyspnoea, hypertension, tachycardia, atrial and ventricular arrhythmias, and myocardial ischemia. MA abusers often go through a repeated pattern of frequent drug administrations followed by a period of abstinence. Previous studies have focused largely upon the chronic effect of MA intake to major organs, such as the brains and the heart, by using animal experiments. However, there is a lack of research into the effects of acute dose of MA, especially pertaining to the heart. To clarify the effect of MA on myocardium, 22 male Wister rats aged six weeks were divided into MA, Placebo (P) and Control (C) group were examined following single intraperitoneal administration of MA at a dose of 50 mg/kg body weight. Normal saline was similarly injected in P group. Light microscopic changes was seen in the myocardium of MA treated group including cellular infiltration, with clusters of macrophage-like cells having large nuclei and little cytoplasm evident in the sub-endocardium region. There were presence of few macrophages, leucocytes, and spindle-like fibroblasts. Bringing in to account of cardiac changes by a single dose of MA, slogan should be voiced out to leave methamphetamine.
    Matched MeSH terms: Central Nervous System Stimulants/toxicity*
  16. The Use of Methylphenidate for Physical and Psychological Symptoms in Cancer Patients: A Review
    Andrew BN, Guan NC, Jaafar NRN
    Curr Drug Targets, 2018;19(8):877-887.
    PMID: 28322161 DOI: 10.2174/1389450118666170317162603
    BACKGROUND: One of the goals of cancer treatment is symptoms management especially at the end stage. The common symptoms in cancer include pain, fatigue, depression and cognitive dysfunction. The available treatment options for symptom management are limited. Methylphenidate, a psychostimulant, may be of benefit for these patients. In this report, we review the use of methylphenidate for symptoms control in cancer patients.

    METHOD: Electronic literature search on PubMed was conducted using the following keywords: methylphenidate, cancer, carcinoma, oncology, oncological and tumour. We identified forty two relevant studies and publications on the use of methylphenidate in cancer patients to be included in this review.

    RESULTS: Methylphenidate was found to have some evidence in reducing opioid-induced sedation, improving cognitive symptoms and reduction of fatigue in cancer patients. Nevertheless, the results were inconsistent due to variations in the study populations, study design and outcome measures, among others. There was minimal evidence on its use in treating depression. Otherwise, methylphenidate was generally well-tolerated by patients.

    CONCLUSION: This review potentially supports the use of methylphenidate for opioid-induced sedation, cognitive decline and fatigue in cancer patients. Further placebo-controlled trials would help in strengthening the evidence for this treatment.

    Matched MeSH terms: Central Nervous System Stimulants/adverse effects; Central Nervous System Stimulants/therapeutic use*
  17. Fulltext The Influence of Audio-Visual Cueing (Traffic Light) on Dual Task Walking in Healthy Older Adults and Older Adults with Balance Impairments
    Kaewkaen K, Wongsamud P, Ngaothanyaphat J, Supawarapong P, Uthama S, Ruengsirarak W, et al.
    Malays J Med Sci, 2018 Feb;25(1):67-74.
    PMID: 29599636 DOI: 10.21315/mjms2018.25.1.8
    Background: The walking gait of older adults with balance impairment is affected by dual tasking. Several studies have shown that external cues can stimulate improvement in older adults' performance. There is, however, no current evidence to support the usefulness of external cues, such as audio-visual cueing, in dual task walking in older adults. Thus, the aim of this study was to investigate the influence of an audio-visual cue (simulated traffic light) on dual task walking in healthy older adults and in older adults with balance impairments.

    Methods: A two-way repeated measures study was conducted on 14 healthy older adults and 14 older adults with balance impairment, who were recruited from the community in Chiang Rai, Thailand. Their walking performance was assessed using a four-metre walking test at their preferred gait speed and while walking under two further gait conditions, in randomised order: dual task walking and dual task walking with a simulated traffic light. Each participant was tested individually, with the testing taking between 15 and 20 minutes to perform, including two-minute rest periods between walking conditions. Two Kinect cameras recorded the spatio-temporal parameters using MFU gait analysis software. Each participant was tested for each condition twice. The mean parameters for each condition were analysed using a two-way repeated measures analysis of variance (ANOVA) with participant group and gait condition as factors.

    Result: There was no significant between-group effect for walking speed, stride length and cadence. There were also no significant effects between gait condition and stride length or cadence. However, the effect between gait condition and walking speed was found to be significant [F(1.557, 40.485) = 4.568,P= 0.024, [Formula: see text]].

    Conclusion: An audio-visual cue (simulated traffic light) was found to influence walking speed in both healthy older adults and in older adults with balance impairment. The results suggest that audio-visual cues could be incorporated into healthy lifestyle promotion in older adults with balance impairment.

    Matched MeSH terms: Central Nervous System Stimulants
  18. Kinetics and mechanism of the alkaline hydrolysis of securinine
    Lajis NH, Noor HM, Khan MN
    J Pharm Sci, 1995 Jan;84(1):126-30.
    PMID: 7714735
    The hydroxide ion-catalyzed hydrolysis of securinine involves the ring opening of the lactone moiety. The rate of hydrolysis is insensitive to the ionic strength. The observed pseudo-first-order rate constants reveal a decrease of approximately 4-fold due to the increase in the MeCN content from 4 to 50% (v/v) in mixed aqueous solvent. The temperature dependence of the rate of hydrolysis follows the Eyring equation, which yields delta H* and delta S* as 11.0 kcal mol-1 and -34.5 cal deg-1 mol-1, respectively. The hydroxyl carboxylate product of the alkaline hydrolysis of securinine is shown to undergo cyclization in acidic medium to yield securinine. The observed pseudo-first-order rate constants for cyclization increase linearly with an increase in [H+]. The change in the content of MeCN from 3.8 to 47.2% (v/v) in mixed aqueous solvents does not show an effect on the rate of the cyclization reaction. The most plausible mechanisms for alkaline hydrolysis and acid cyclization reactions are also discussed.
    Matched MeSH terms: Central Nervous System Stimulants/chemistry*
  19. Fulltext Social drug use in the parturient: implications for the management of obstetrical anaesthesia
    Kuczkowski KM
    Med J Malaysia, 2003 Mar;58(1):147-54; quiz 155.
    PMID: 14556345
    Maternal use of social drugs in pregnancy continues to increase--worldwide. Although a great deal has been learned regarding the implications of illicit drug abuse in pregnancy (cocaine, amphetamines, hallucinogens), the use of social drug in pregnancy has received far less attention. This article reviews the consequences of the social drug use in pregnancy including ethanol, tobacco and caffeine and offers recommendation for anaesthetic management of these potentially complicated pregnancies.
    Matched MeSH terms: Central Nervous System Stimulants/adverse effects*
  20. The rise of methamphetamine in Southeast and East Asia
    McKetin R, Kozel N, Douglas J, Ali R, Vicknasingam B, Lund J, et al.
    Drug Alcohol Rev, 2008 May;27(3):220-8.
    PMID: 18368602 DOI: 10.1080/09595230801923710
    Southeast and East Asia has become a global hub for methamphetamine production and trafficking over the past decade. This paper describes the rise of methamphetamine supply and to what extent use of the drug is occurring in the region.
    Matched MeSH terms: Central Nervous System Stimulants/adverse effects; Central Nervous System Stimulants/supply & distribution*
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